The online maps that reveal the noisiest parts of the country

The Government hopes they will help reduce noise pollution and protect designated quiet areas.

The maps, which cover 23 urban areas in England, are available to the public on the Department for Environment and Rural Affairs website.

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This online map of London is just one of those released by Defra to show levels of noise in the country

Click here to find out about noise pollution levels in your area

Users are able to search by postcode for information showing different levels of noise over a 24-hour period.

Environment Minister Jonathan Shaw said: 'Factors like transport and industry are a necessary part of modern life.

But we need to look at what further practical steps we can take to make people's lives more tranquil. These maps provide the most comprehensive snapshot yet of noise in our country, all at the click of a mouse.

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The famous shape of the Thames and London shows the main roads in darker colours to indicate how noisy they are

They will provide a springboard to go forward and tackle unnecessary and unreasonable noise pollution.

'"We will use them to draw up action plans to reduce noise where practical from major roads and railways, as well as from urban areas.

"The plans will include measures to protect designated quiet areas from any increase in noise."

The maps cover 50,000 miles of urban roads, 17,000 miles of major road networks, almost 3,000 miles of railways and the areas around 18 airports.

They use isolines, which are similar to contours and link areas of equal decibel level. A colour code defines areas of different noise levels.

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At the top end of the scale, noise levels greater than 75 decibels - the equivalent of a loud radio or a very busy street - were found within a few miles radius of airports and next to motorways, railways and heavy industry.

The site also includes information on the number of people exposed to different levels of noise, which is measured from the threshold of hearing (0 decibels) to the threshold of pain (120 decidels).

For example, noise in a library averages about 40 decibels, while a pneumatic drill measures 95 decibels.

The mapping, which was carried out using computer modelling techniques during 2006 and 2007, is in line with the EU Environmental Noise Directive.

This requires member states to make and publish strategic noise maps for all major roads, railways and airports, as well as for large urban areas.

Researchers have previously linked loud noise to illness and educational problems in children.

A German study of more than 2,000 heart attack patients in the European Heart Journal found that those exposed to more than 60 decibels had an increased risk of heart attack.

The areas involved are: :: Birkenhead :: Blackpool :: Bournemouth :: Brighton :: Bristol :: Coventry :: Hull :: Leicester :: Liverpool :: London :: Manchester :: Nottingham :: Portsmouth :: Preston :: Reading :: Sheffield :: Southampton :: Southend :: Teesside :: The Potteries :: Tyneside :: West Midlands :: West Yorkshire